Method for correcting errors by de-embedding dispersion parameters network analyst and switching module

ABSTRACT

The invention relates to a method for correcting errors by de-embedding dispersion parameters of a measuring object associated with measuring gates ( 11 ), said parameters being measured by a vectorial network analyst comprising n measuring gates. The aim of the invention is to create a universal, precise and fast means of correcting errors of dispersion parameters. To this end, the method comprises the following steps: formula ( 1 ) two-port calibrations are carried out on different calibrating standards in any order in the active state between the measuring gates ( 11 ), as a basis for a first error correction; the reflection parameters of at least one part of the n measuring gates ( 11 ) are determined in the inactive state, by means of the results of two-port measurements carried out on at least one calibrating standard switched in the active and/or inactive state on measuring gates ( 11 ), as a basis for a second error correction. The invention also relates to a network analyst and to a switching module for a network analyst, said elements comprising adequate means.

[0001] The invention concerns a procedure for error correction by thede-embedding of a dispersion parameter, which has been measured with ann-gate containing, vectorial network analyzer, wherein the dispersionparameter relates to a measured object connected to the said gates. Theinvention also concerns a vectorial network analyzer for the saidprocedure as well as a circuit module for the said network analyzer.

[0002] In high frequency technology, the behavior of circuits isnormally described in terms of dispersion parameters. The dispersionparameters represent complex reflection and transmission parameters of acircuit and join ingoing and outgoing waves with one another. Arepresentation of this type where complex reflection and transmissionparameters are concerned is especially well suited to the physicalrealities of the problems brought forth in high frequency technology.

[0003] Thus, for example, a circuit, which is formed by a linear 2-gate,and is incorporated in the dispersion parameters by means of itsdispersion matrix [S], can be completely described. If the waves, whichrespectively run to one gate of the 2-gate, are designated as a₁ and a₂and those waves which depart from respectively one gate of the 2-gate,and propagate themselves in a reverse direction, are designated by b₁and b₂, then, for the dispersion matrix [S] the following validrelationship serves: $\begin{pmatrix}b_{1} \\b_{2}\end{pmatrix} = \underset{\underset{= {\lbrack S\rbrack}}{}}{\begin{pmatrix}S_{11} & S_{12} \\S_{21} & S_{22}\end{pmatrix}\begin{pmatrix}a_{1} \\a_{2}\end{pmatrix}}$

[0004] Experience in the practice allows it to be known, that for thedetermination of the dispersion parameter, it is advantageous to employa circuit of a network analyzer to which the circuit of the measuredobject can be connected. By means of such a network analyzer, the wavesapproaching the measured object are input and captured at themeasurement positions. Likewise, the waves sent in the oppositedirection are captured at measurement stations. From these measuredvalues, it is then possible to determine the dispersion matrix [S].

[0005] The goal of every n-gate measurement by means of a networkanalyzer is to determine the dispersion parameter with the greatestprecision. In any case, error interferences occur throughout the networkanalyzer itself, such as, for example, improper interlinkage ormismatching, which falsify the results of measurements.

[0006] The precision of the measuring capacity of the network analyzer,as a rule, can be substantially improved by a system error correction.Where the system error correction is concerned, measurement takes placewithin a calibration process, this being the so-called calibrationstandards, that is, measurement objects, which are partially or fullyknown. From these measurement values and through special computationalpaths, one obtains correction data. With these correction data and acorresponding correction computation, one obtains for each optionalmeasured object from the rough measurement values, corrected dispersionparameters, which are then free from the said system error of thenetwork analyzer.

[0007] De-embedding is to be understood as a situation wherein after acalibration has been made as described, one has obtained dispersionparameters, which are not yet sufficiently error-free, and subsequentlythe said dispersion parameters are subjected to a second measurementcorrection. This can be, in the simplest case, a multiplication with aninverse iterative matrix of a known circuit line between the networkanalyzer and the measured object. As a rule, a good calibration in thereference planes of the measured object is more exact than an additionalde-embedding step. However, a calibration is often time consuming andcomplex, and in many cases the exactness of a de-embedding step issufficient. In the literature, de-embedding is designated as a“Two-Tier-Calibration”, which also makes clear, that when de-embeddingis practiced, a two-stage calibration, i.e. a two-stage error-correctivemeasure of the raw measured values is being undertaken.

[0008] Principally, network analyzers are a means of measuringelectronic equipment of one and 2-gate parameters in a range of, forinstance, electronic semiconductor components to antennas. These 1-gateand 2-gate calibration procedures form, however, no fully sufficientbasis for error correction in the measurement of multigate objects. Oneproblem with multigate measurement is found therein, in that, namely allgates of the measured object are interlinked.

[0009] Thus one cannot obtain, from a single point of measurement, avalue for the waves departing, then at the next measuring point, achievea value for the reflected wave, and finally at a third measurementpoint, pick up a value for a transmitted wave, which value would beindependent of the connection terminals of the multigate object.

[0010] However, for several years, network analyzers with a nearlyoptionally large number n of measuring gates have been put to use forthe detection of the complex reflection and transmission characteristicsof multigate measured objects. Procedures in accord with this have beendescribed in the documents DE 199 18 697 and DE 199 18 960. DE 199 18960 is based on the use of a 7-term-procedure for 2-gate measuring, andDE 199 18 697 is based on the use of a 10-term procedure for 2-gatemeasuring. The calibration procedures presented in the saiddocumentation for the error module for n-gate network analyzers aredirect multigate (or multiport) calibration procedures, which, to besure, are exact, but however, with which, in practice, the necessarymeasurements and corrections are very time consuming. The result of thisis, that these procedures cannot be employed for network analyzers,which exhibit three or four measurement positions, which by means of twoinner gates and a circuit matrix are connected with the gates on themeasured object. These network analyzers present, however, by far thelargest group of applied network analyzers.

[0011] In modern network analyzers with four measuring positions, therehas been one in the dissertation publication “Safe Procedure for theCalibration of Network Analyzers for Coaxial and Planar Line Systems”,Institute for High Frequency Technology, Ruhr University, Bochum, 1995,from H. Heuermann's descriptive TRL, i.e. “Through Line ReflectanceCalibration Procedure”. In this procedure, there is required, aside fromthe through connection T, the remaining two standards L and R, whichneed be only partially known. In the said publication, however, it hasbeen shown, that the TRL-procedure can be seen as essentially a specialcase of a general theory for the so-called “two error matrix 2-gatemodel”.

[0012] As measured objects of multiport measurements, first, there is aseries of objects with unsymmetrical terminal connections (as a rule, 50Ω-gates) such as couplers, signal parts, and frequency selectivefilters, and second, objects to be considered with connection terminalsof various types, such as, for instance, symmetrical members andSAW-filters (i.e., Surface Acoustic Wave filters). In the case of thelatter, the state of the technology is, that the differential mode, bymeans of an additional working step under the limitations of an idealtransformer is retroconverted into an unsymmetrical mode.

[0013] Thus, the invention has the purpose of making available aprocedure, a network analyzer and a circuit module, which permit auniversally applicable, exact and non-time consuming error correction ofthe dispersion parameters of a measured object, as measured by means ofa network analyzer.

[0014] First, this purpose is achieved, in accord with the invention, bya procedure as stated in claim 1.

[0015] Second, the purpose is achieved, in accord with the invention, bya network analyzer as stated in claim 10.

[0016] Third and finally, the purpose is achieved, in accord with theinvention, also by a switching module for a network analyzer as statedin the claims.

[0017] Between the pairs of n gates of a network analyzer, byappropriate connection, a calibration standard signal path can beformed. Where n gates are concerned, $k = {n \cdot \frac{n + 1}{2}}$

[0018] various combinations of pairs of gates are possible, andtherewith, also k of such signal paths per pair of gates. The necessarycapture means for the 2-gate calibration from signals approaching thegates, and those signals emitted from the gates can be optionallyconstructed. Thus, the n gates of the network analyzer can be connectedboth by a circuit matrix and inner gates with 3 or 4 measuringpositions, as well as being connected by only one switch matrix with 3,4 or n−1 measuring positions, and as well, even without a switch matrixdirectly to 2·measuring positions.

[0019] Calibration standards may be established as in the knowncalibration procedures involving n-gates, 2-gates, and/or single to ntimes gates, which, with one exception, are advantageously completelyknown, or are self-calibration. As is discussed in greater detail in theabove said dissertation document, standards with self-calibrationcapabilities are, at this time, only based on 2-gate standards, whichare measured with at least 4 measuring positions. The exceptionmentioned above consists, as in the known 2-gate calibration procedure,of at least one, required 2-gate, limited transmission damping, which isnot advantageously completely known or is self-calibration.

[0020] If, however, the transmission damping of this 2-gate becomesknown, then, correspondingly installed n-times single gates need not becompletely known. The n-times 1-gates, which are capable of beinginstalled in the invented procedure and in the invented network analyzerwith the rank of a calibration standard, can be either an n-gateconsisting of n 1-gates, or a 1-gate which is connected and measured ateach of the n-gates.

[0021] The invention bases itself on the 2-gate calibration procedureimplemented in known network analyzers. After such a known calibrationprocedure for the availability of error terms for a first errorcorrection has been carried out, the invention allows, by means of avery simple, additional de-embedding step with only a few measurements,the obtaining of exact multiport values, which give indications on themultiport behavior of the measured object.

[0022] For each gate, various reflection factors exist for variousconditions. Active states are given, when the gate is switched to sendor receive. An inactive state exists, when the gate is shut off. Theknown 2-gate calibration procedures determine and make use ofexclusively the reflection parameters of 2-gate in the active state.Thereby, in any case, the correlations between the n-gates cannot betaken into consideration, which determine the multiport behavior of themeasured object.

[0023] The proposed de-embedding step is found therein, in that after aknown k-times 2-gate-calibration, the reflection factors of at leastsome of the n-gates of the network analyzer are to be determined in theshutoff condition. This determination is executed with the results ofthe 2-gate measurements on at least one calibration standard connectedat the gates in the active and/or the inactive state.

[0024] For network analyzers, which principally possess three or fourmeasuring positions, which are connected by two inner gates with then-gates, the inactive and the active reflection behavior of the gatesare different. In the case of such network analyzers the inactivereflection factors are determined, while respectively, on the senderside the reflections of the 2-gate are measured. During this time, thegate, which functions otherwise as a receiver, is shut off.Additionally, if the measured inactive reflection factors are freed oferror, then, particularly because of the connected calibration standardbetween the gates the measured factor diverts from the actually inactivereflection factor. In this case, the 2-gate are additionally measured inboth directions with the same calibration standard, while respectively;one gate is a sender and the other gate functions as a receiver.Furthermore, both gates are switched to the active state. Themeasurement results can then be applied to extinguishing the error ofthe measured inactive reflection parameter.

[0025] For network analyzers, which exhibit 2·n or n+1 measuringpositions, the active and the inactive reflection behaviors of the gatesare identical. On this account, in this case it becomes necessary toexclusively measure the 2-gate, while both gates are switched to active.In regard to determined reflection parameters of the gates in theinactive state, then simply, the reflection parameter of the gates inthe active state can be used.

[0026] The determined reflection parameters of the gates in the inactivestate can then form a base for a second error correction of thedispersion parameter by which the multiport behavior can be estimatedwith a high degree of precision. With the proposed procedure, messages,decontaminated of crosstalk and faulty mix can be carried out, both incoaxial systems as well as in semiconductor substrates.

[0027] Being based on the invented procedure and the invented networkanalyzer, that is to say, the circuit module, it is possible, from thenow available 2-gate-solution to very rapidly convert complex multiportsolutions for the network analyzer. This requires far less loss of timethan the known multiport procedure. The invented procedure presents, inthis way, a De-embedding, Multiport Procedure (hereinafter, “DMV”),which essentially is less expensive than the known multiport calibrationprocedure based on a few calibrations. Very importantly, the inventionpermits applications on network analyzers, which have 3 or 4 measurementpositions and wherein a switching matrix is connected to the gates,which are not possible with the known multiport calibration procedure.

[0028] A particular advantage of the proposed procedure lies in thesimple possibilities of implementation in a network analyzer. Further,the procedure has superiorities over the known multiport-calibrationmethod, in that not all signal paths need be measured, if only one or afew dispersion parameters are being sought. For a comprehensive errorcorrection of a dispersion matrix of a measured object, however, all kpossible signal paths between two gates must be measured and therefromthe reflection parameters of combined gates in the active state aredetermined.

[0029] The claims of the here presented procedure regarding thecalibration standards are the same as in the case of known 2-gate andmultiport calibration method. This is a very important aspect for theavailability of the calibration standard and thus also for the practicalapplication thereof. Since the presented procedure permits theapplication of a very large number of calibration standards, this hasthe result of enabling in each circuit a possibility for the preciserealization of the said standards and thereby an entirely newperspective in the measurement of a plurality of gates.

[0030] Even when the reflection factors of all n gates should bemeasured, the number of the necessary contacts of individual standardsin the case of the proposed procedure is not greater than is the casewith the multiport, 10-term-method from DE 199 18 697 A1. Principally,in comparison to the said multiport, 10-term-method from DE 199 18 697,even additional connections are called for.

[0031] Advantageous embodiments of the invented procedure and thenetwork analyzer are evident in the subordinate claims.

[0032] In a preferred embodiment of the invented procedure, for thedetermination of the reflection factors of 2-gate in the inactive state,the through connections are maintained as in the case of the established2-gate calibration in accord with a known procedure, so that noadditional connection effort is necessary. However, as compared to abasic 2-gate, 7-term method, a reduced connection expense is gained.Moreover, the already established results obtained from the said throughconnection calibrations of the 2-gates in the active state can be used.To be sure, for each network analyzer for each reflection parameter tobe determined of a gate in the inactive state must undergo a further2-gate measurement with respectively a switched off gate must be carriedout. However, essentially, much more time consuming than themeasurements themselves is the making of new connections. The inventedprocedure also permits the de-embedding step with the inclusion ofcarrying out the implementation of the well known 2-gate errorcorrection procedure in each network analyzer.

[0033] The proposed de-embedding procedure can operate with all 2-gatecalibration methods in accord with the 10-term and the 7-termtechnologies, which, for example, have been described as starting pointsin the already mentioned documents DE 199 18 697 A1 and DE 199 18 960A1. For the necessary calibration measurements up to the number k, asbasis for the first error correction, it suffices if one has availablethe conventional standards for the 10 term or the 7 term procedures, forexample, TMSO, TMR, or TLR. In these acronyms,

[0034] T=through connection

[0035] M=known impedance

[0036] S=Short circuit

[0037] O=Dry run

[0038] L=Line

[0039] R=Reflection Standard

[0040] Advantageous concrete embodiments with the invented combinational2-gate calibration procedure are to be found in the subordinate claims 5to 8.

[0041] There are four different network analyzer designs, which can beconsidered technically advantageous. In each of these designs, theinvented procedure may be applied.

[0042] As a first, and most favorable from a price standpoint, is anetwork analyzer principally marked by three measuring positions. Two ofthe three measuring positions are respectively and directly joined totwo inner gates, and the third measuring position can be joined with thetwo inner gates by a switch. A switching matrix connects the two innergates of the network analyzer with the n outer gates and in this wayrealizes the k necessary signal paths. With this design, none of theknown multiport calibration methods may be applied.

[0043] Going beyond the above, consideration can be given to a networkanalyzer as a quick, but not so economically favorable design, in whichthe n gates are connected by a switching matrix, but an inner gate withn+1 measuring positions is lacking. Such a rapid design, for example, ismore closely described in the DE 199 18 697 A1.

[0044] For these first two designs, in the procedure in accord with theinvention, k 2-gate-10-term methods are carried out. The requirementsregarding the calibration standards are the same as that from the knownmultiport-10-term procedure of the DE 199 18 697 A1. What is new is theinvented, additional determination of the magnitude of the reflection ofthe n gates in the inactive state, whereby, in the second case, thereflection magnitudes of the n gates in the inactive state can be setequal to the reflection magnitudes of the n gates in the active state.These first two designs can especially be applied with the proposedproceeding as outlined in the subordinate claim 5.

[0045] As a third design, and once again favorable in price, referenceis made to a network analyzer with four measuring positions. In thiscase, respectively, two of the measuring positions are directlyconnected with respectively one of two inner gates of the networkanalyzer. As in the first design, the two inner gates of the networkanalyzer are connected through a switching matrix with the n outer gatesof the thus realized multiport network analyzer. Also, for this design,none of the known multiport calibration procedures can be applied.

[0046] Finally, as an additional, again rapid but very expensivealternative, attention can be called to a network analyzer, wherein then gates, absent a connected switching matrix, are bound directly with2·n measuring positions. Such a design is more closely described in theDE 199 18 960.

[0047] For the procedure in accord with the invention, for the two laststated designs, advantageously k 2-gate-7-term procedures are executed.The requirements as to calibration standards and the number is the sameas that of the DE 199 18 960 A1 known multiport calibration method, butthe number of the contacts is different. What is new, is once again, forthe determination of the reflection magnitudes of the n-gates in theinactive state, which determination is necessary for de-embedding,wherein, in the fourth design, the reflection magnitudes of the n gatesin the active state can be set equal to the reflection magnitudes of then gates in the active state. The 10-term-procedures can, in this design,also be applied, but requires, however, high quality and more numerouscalibration standards and calibration related measurements. Thesedesigns can be applied, especially with one of the procedures proposedin the subordinate Claims 6 to 8.

[0048] If, in a network analyzer, 2·n or n+1 measuring positions areprovided, then the n gates can be connected directly, that means, theycan be connected by the equivalent of a throw switch with the measuringpositions. As alternative, it is possible that a switching matrix can beprovided, which has the capability of connecting each of the n gates ofthe network analyzer respectively to at least one of the measuringpositions with two inner gates of the network analyzer. The n+1 or 2·nmeasuring positions can, in this case, also be integrated in theswitching matrix. In this manner, a network analyzer requires only twoinner gates, but possesses nevertheless n+1 or 2·n measuring positions.

[0049] The claims 6 to 8 link the application of the known 7-term,2-gate calibration procedure with the names TAN, TNA, TRL, LLR, LRL,TAR. TMR, TRM, UMSO, TMN, LNN, TZU, TZY, TYU, LZY, ZZU, YYU, etc. where:

[0050] T=Through

[0051] R=Reflect

[0052] L=Line

[0053] A=Attenuator

[0054] M=Match

[0055] U=Unknown

[0056] S=Short

[0057] O=Open

[0058] N=Network

[0059] Z=Series Resistance

[0060] Y=Parallel Resistance.

[0061] For details of these procedures, reference is made to thedissertation publication already mentioned above. All these algorithmsbelonging to the class of the 7-term-process permit themselves, withtheir advantages, to be implemented in an invented network analyzerwithin the framework of the invented procedure. All of the proceduresare used k-times in their classic application form. In accord with this,each 2-gate standard must be contacted k-times and each 1-gate standardmust be contacted k-times. On this account, the procedure presentedhere, that is, the total calibration procedure departs clearly from themultiport 7-term calibration method as taught by DE 199 18 960 A1. Inthe case of multiport problems with more than three gates, theseprocedures have greatest interest, which procedure contains the fewest2-gate standards, since k is much greater than n.

[0062] In the subordinate claims 7 and 8, the practically, verymeaningful usage of the 7-term procedures TRL and TMR were emphasized.In the case of the very interesting TMR-DMV, a multitude of alternativesin the succession of the contacting of the 1-gates become available forselection upon the choice of the calibration standard combinations.

[0063] However, it is presupposed, that it is necessary to once connectall gates by means of a known 2-gate connection (as a rule, a throughbinding T).

[0064] Further, at each gate, a known impedance connection must beconnected, i.e. a wave sink M, and a reflection standard R, thereflection behavior of which, at each gate must be essentially equal, ornot known.

[0065] In claim 9, in an extended manner, is proposed an advantageouspossibility for the treatment of measured objects with differential andcommon mode at the contact terminals. In accord with this, the measuredobject is described, instead of by the customary dispersion parametersfor an unsymmetrical mode, is described with dispersion parameters forthe common and differential modes. The procedure distinguishes itselfabove the method used up to now with the ideal transformer, in that alldissipation mechanisms have an under-support as individual, physicallyrecoverable quantities, thus clearly providing more information to thedevelopers allowing them to improve their product in its electricalcharacteristics. With this embodiment of the invented procedure, objectssuch as SAW filter and symmetrical members can be analyzed simply,quickly and in great detail.

[0066] The means of the invented circuit module are advantageouslyimplemented in software. Further, the circuit module can show itself asa stand-alone new unit or as an available component in the currentnetwork analyzer, wherein the said module is additionally integrated.

[0067] In the following, the invention will be described and explainedin greater detail, with the aid of the drawing. There is schematicallyshown in:

[0068]FIG. 1 a network analyzer with 3 measuring positions, 2 innergates and n outer gates,

[0069]FIG. 2 a network analyzer with 4 measuring positions, 2 innergates and n outer gates,

[0070]FIG. 3 a network analyzer with 3 measuring positions and n outergates,

[0071]FIG. 4 a network analyzer with 4 measuring positions and n outergates,

[0072]FIG. 5 a network analyzer with 2·n measuring positions and n outergates,

[0073]FIG. 6 the determination of active reflection factors in a networkanalyzer per FIG. 1

[0074]FIG. 7 the determination of inactive reflection factors in anetwork analyzer per FIG. 1, and in

[0075]FIG. 8 a block circuit diagram of a network analyzer in accordwith FIG. 2, for which the second error correction of dispersionparameters has been made clear.

[0076] First, embodiment examples of a network analyzer is describedwith the aid of FIGS. 1-5, which show an arrangement wherein theinvented de-embedding procedure may be applied.

[0077]FIG. 1 presents a network analyzer with three measurementpositions 15, two inner gates 22 and n outer gates 11. A service andoperating unit 21 is connected to two inner gates 22 of the networkanalyzer by three measurement positions, namely A, B and R as well as byhigh frequency lines 18, 19. The two inner gates 22 are, on their ownpart, connected through a switching module 20 with n outer gates 11. Twoof the measurement positions A and B capture back-running signals fromthe outer gates 11 and one of the measurement positions, i.e., R, picksup the signals directed to the outer gates 11. The high frequency supplylines 18, 19 are meanwhile used to conduct incoming signals to the outergates 11, whereby also a (not shown) reflectometer also guides therespective signal to the measurement position R for the waves directedto that point. The active and the inactive behavior of gates differ inthis network analyzer. The twofold error correction of measuredparameters of a measured object is done in this network analyzer and inthe network analyzers described in the following in the processing unit21, in which also corresponding error terms for the first and the secondcorrection are determined and stored. For such a network analyzerneither the known 7-term nor the 10-term multiport calibration procedurecan be allowed to run. As a basis for the invented procedure, n 7-term2-gate calibration procedure can be used, however, the 10-term 2-gatecalibration method is also acceptable.

[0078]FIG. 2 brings forth a network analyzer with four measuringpositions 15, two inner gates 22 and n outer gates 11. One service andprocessing unit 21 is connected by four measuring positions 15, namelyA1, B1, A2, B2 and two high frequency feed lines 18, 19 are connectedwith two inner gates 22 of the of the network analyzer. These innergates 22 are in electrical communication with a switch module 20 havingn external gates 11. The high frequency lines 18, 19 emit on their ownpart, signals traveling to the external gates 11. Since, in this case,four measuring positions are provided, it is possible, thatadditionally, within the equipment, reflected waves can be captured. Theactive and the inactive behavior of gates are, once again, different.Also, in this case, neither the known 7-term nor the known10-term-multiport calibration method has been applied. However, as abasis for the invented procedure, because of the possibility of thecapture of the reflected waves within the equipment, both the10-term-2-port calibration procedure as well as the 7-term 2-gatecalibration procedure must be given consideration.

[0079]FIG. 3 presents, once again, a network analyzer with threemeasuring positions 15 and n external gates 11. In this case, a serviceand processing unit 21 is connected by the three measuring positions 15,these being A, B, and R. The high frequency lines 18, 19 are directlybound to a switch module 20. The switch module 20 makes possible adirect connection between the measurement position 15 and the n outergates 11. Contrary to the network analyzers of the FIGS. 1 and 2, theinactive and the active behavior are identical. In this design, theknown 10-term-multiport procedure could be employed. As a basis for theinvented procedure, once more, no 7-term, 2-gate calibration method canbe used, but however, again the 10-term, 2-gate calibration system isacceptable.

[0080]FIG. 4 presents, similarly to the network analyzer of FIG. 3, anetwork analyzer in which the measuring positions 15 and the highfrequency lines 18, 19 run directly to a switch module 20 with n outergates 11. In FIG. 4 are provided, in any case, once again four measuringpositions 15, namely A1, B1, A2, B2. Alternately, also n+1 measuringpositions could be provided. As in the case of the network analyzer ofFIG. 3, the inactive and the active behavior is identical. In thisdesign, besides the known 10-term, multiport procedure, also the 7-term,multiport procedure can be applied. As in the case of the networkanalyzer of FIG., 2, as a basis for the invented procedure in addition,consideration is given to both the 7-term, 2-gate calibration procedureas well as the 10-term, 2-gate calibration procedure.

[0081] Finally, in FIG. 5, we see a network analyzer, wherein a serviceand processing unit 21 is connected with 2·n measuring positions, indetail, these being A1, B1, An, Bn, and by a high frequency cabledirectly to a connection module 23. This connection module 23 enables aconnection of the measuring positions 15 with the n outer gates 11without any switching action, since for each outer gate 11, onemeasurement position A1 to An is provided for thereto directed waves anda measuring position B1-Bn is provided for backflow waves. As in the twonetwork analyzers from FIG. 3 and FIG. 4, the inactive and the activebehavior is identical. Also, with this design, the known 10-term,multiport procedure and the known 7-term multiport procedure can beapplied. As a basis for the invented procedure, both the 7-term, 2-gatecalibration procedure and the 10-term, 2-gate calibration procedure canbe employed.

[0082]FIG. 6 demonstrates schematically the known determination ofactive reflection factors by 2-gate measurings in a network analyzersuch as seen in FIG. 1. FIG. 7 shows, again schematically the inventeddetermination of inactive reflection factors by 2-gate measuring in anetwork analyzer such as presented in FIG. 1. In both figures, the samesection from a network analyzer with a built-in calibration standard 10is shown.

[0083] In the two FIGS. 6 and 7, one of the high frequency lines 18 isconnected through a first inner gate 22 and through the switch module 20to a first outer gate 11 of the n outer gates. By an inserted throughconnection 10 serving as a calibration standard, the first outer gate 11is connected with a second of the n outer gates. The two gates 11 form a2-gate to be measured. The second outer gate 11 is, by the switch module20 and by the second inner gate 22 connected with the second highfrequency supply line 19. In the switch module 20 is provided a firstswitch 24, for a switchable connection between the first inner gate 22and the first outer gate 11, which can connect the first inner gate 22either with the first outer gate 11 or to ground by means of aresistance 25. A corresponding second switch 24 is provided in theswitching module 20 for a switchable connection between the second innergate 22 and the second outer gate 11. Further presented, are the threemeasuring positions 15 which are connected to the two inner gates 22.The measuring position R is, in this arrangement, by means of areflectometer is capable of capturing the oncoming waves which areapproaching the first outer gate 11. Similarly, the measuring position Ais likewise capable of capturing the back flowing waves from the outergate 11. The measuring position B captures the waves coming from thesecond outer gate 11.

[0084] Next, the determination of active reflection factors will beexplained with reference to FIG. 6. For the determination of the activereflection factors of the second outer gate 11, the first outer gate 11serves as a sender and the second outer gate serves as a receiver. Inthis regard, for one thing, in the switching module 20, by means of thefirst switch 24, a connection is established between the first innergate 22 and the first outer gate 11, and by means of the second switch24 a connection is brought about betwen the second outer gate 11 and thesecond inner gate 22.

[0085] Subsequently, by means of the first high frequency line 18, asignal is sent over the first inner gate 22 and the switching module 20onto the first outer gate 11. As this happens, the measuring position Rcaptures a measured value for the signal. A portion of the approachingsignal to the first outer gate 11 is immediately reflected and directedback through the switching module 20 and guided to the first inner gate22 of the measuring position A. The non-reflected part of the signal isconducted through the calibration standard 10 to the second outer gate11. At this second outer gate 11, another portion of the signal isreflected and travels over the first outer gate 11, the switch module 20and the first inner gate 22, likewise guided to the measuring positionA. The remaining residual signal is conducted over the second outer gate11, the switching module 20 and the second inner gate 22 on the secondhigh frequency line 19, whereby the measuring position B picks up thisportion of the signal.

[0086] In the same manner, according to connection, the second outergate 11 can serve as sender, and the first outer gate 11 can be thereceiver, in order that the corresponding measurement values for theactive reflection factor of the first outer gate 11 can be determined.The measurement position R is, for this purpose, is so switched, that itis capable of capturing the waves approaching the second outer gate 11.From the captured values obtained from the measurement positions 15, ina known manner, the active reflection factors of the two outer gates 11can be determined.

[0087] The determination of inactive reflection factors in the case of anetwork analyzer, wherein the active and inactive behaviors aredifferent, will now be explained with reference to FIG. 7. Such adetermination is not known in conventional calibration procedures. Forthe determination of the inactive reflection factors, once again, at thebeginning the first outer gate 11 plays the role of sender, the secondouter gate, on the other hand is shut off. For the shutting off, in theswitching module 20, the second switch 24 is so positioned, that itconnects the second outer gate 11 with the second resistance 25 insteadof with the second inner gate 22.

[0088] Under these circumstances, then a renewed signal is sent over thefirst high frequency line 18 to the first outer gate 11. A first portionof the signal is again reflected to the first outer gate 11 and anadditional portion is sent to the second outer gate 11. The secondreflected portion differentiates itself however, from the secondreflected portion of the signal in FIG. 6, since the signal at thesecond outer gate 11 now, because of the changed position of the secondswitch 24 is directed to a terminal of resistance 25, instead of throughthe second inner gate 22 on the second high frequency line 19.

[0089] The capture of the approaching and the reflected wavescorresponds to that shown in FIG. 6, only that in this case, that is, nosignal reaches the measurement position B, since the connection to thismeasurement position has be interrupted. However, from the measuredvalues at the measurement positions A and R, now a reflection factor forthe second outer gate 11 in the inactive state can be determined.Additionally, the determined inactive reflection factor, with theavailability of the measurement values for the active reflectionfactors, can be subjected to an error correction, in order to set asidethe influence of the calibration standard 10 between the outer gates 11from the said reflection factor.

[0090] For the determination of the reflection factor for the firstmeasurement position 11 in the inactive state, the procedure is renewedin the opposite direction and carried out with inverted switchpositioning.

[0091] The general problem of n-gates is often reduced to 3-gates forthe sake of clarity. Likewise, FIG. 8 shows, for example, a 3-gatemulti-gate, network analyzer. The multi-gate, network analyzer in thefigure, corresponds to that in the introductory passages of thedescription as an already mentioned third practical, relevant designnetwork analyzer, that is, the network analyzer of FIG. 2.

[0092] The network analyzer of FIG. 8 possesses a signal source 17,which is connected to a real switch 15 with two branches, 18, 19. Eachof the line branches 18, 19 is respectively assigned to connections,which are two assumed ideal measurement positions 15, namely, m1, m2, orm3, m4. Both conductor lines 18, 19 can be electrically joined throughan inner gate 22 and a common switching matrix 20 by likewise assumedideal switches with one optional selection of three error networks 12,13, 14. The switching matrix 20 represents herein, the real switchingmodule from FIG. 2. Each of the three error networks 12, 13, 14 isfinally bound by a gate 11 with a measured object DUT 10. (DUT=DeviceUnder Test=measured object) The measured object can, in one instance, bean object, the reflection parameters and transmission parameters ofwhich are to be determined. Additionally, various calibration standardsare applied for the error-correction of determined dispersionsparameters.

[0093] When a signal, the characteristics of which, such asreproducibility, durable stability, etc., are not yet exact, is emittedfrom source 17, it enters a switch module 16 and is diverted to one ofthe two line branches 18, 19, by which it is conducted to an inner gate22. By means of the switching matrix 20, the signals to the gates 11 ofthe measured object 10, after a reflection to, or a transmissionthrough, said measured object 10, the signals are returned again back tothe line branches 18, 19. The waves which are approaching the measuredobject 10 are designated with a₁, a₂, a₃ and the waves departing fromthe measured object 10 are designated b₁, b₂, b₃, whereby the same indexis assigned to the corresponding gate 1, 2, 3. The accumulated errors ofthe switching matrix 20, the measurement positions 15, and theconnection cable 18, 19 are combined in the respective error-matrices ofthe error-network 12-14.

[0094] For the determination of the dispersion parameters of a connectedmeasurement object 10, one of the measurement positions m₂ or m₃ takes ameasure at one of the line branches 18, 19 for the approaching wave, andthe measurement positions m₁, m₄ take at the corresponding line branch19, 18 a measurement for the back fed, reflected, or transmitted waves.

[0095] Next, the network analyzer is subjected to a 7-term 2-gatecalibration procedure, in order to make available error-terms for afirst error correction of dispersion parameters. Corresponding to theformulation of FIG. 7, then for a second error-corrective measure, theerror-free reflection factors r_(ii) (1=1−3) of the three gates, wherei=1 is assigned to the first gate, i=2 is assigned to the second gateand i=3 is assigned to the third gate.

[0096] In this connection, it is possible for a measured object to havethe dispersion-parameters determined as rough measured values and aninitial error correction to be undertaken on the basis of the error-termof the 7-term, 2-gate calibration procedure. The measured and simplycorrected dispersion parameters for the nine values of a 3×3 dispersionmatrix and are designated by: s_(ij) ^(m) where (i=row 1-3; j=column1-3)

[0097] From the already corrected dispersion parameters of the object tobe measured, and the invented, determined and error-free reflectionfactors r_(ii) it is now possible to determine the “true” dispersionmatrix [S] of the measured object 10 with three measuring gates 11 inthe equation: $\begin{matrix}{\begin{pmatrix}b_{1} \\b_{2} \\b_{3}\end{pmatrix} = {\underset{\underset{\lbrack S\rbrack}{}}{\begin{pmatrix}S_{11} & S_{12} & S_{13} \\S_{21} & S_{22} & S_{23} \\S_{31} & S_{32} & S_{33}\end{pmatrix}}\begin{pmatrix}a_{1} \\a_{2} \\a_{3}\end{pmatrix}}} & (1)\end{matrix}$

[0098] It is now permissible to simply formulate, for a 3-gatemulti-gate network analyzer, by the known signal-flow method, theequations for the de-embedded dispersion parameters, as follows:$\begin{matrix}{S_{11} = {S_{11}^{m} - {S_{13}^{m}S_{31}^{m}\frac{r_{33}}{1 - {r_{33}S_{33}^{m}}}} - {S_{12}^{m}S_{21}^{m}\frac{r_{22}}{1 - {r_{22}S_{22}^{m}}}}}} & (2) \\{S_{22} = {S_{22}^{m} - {S_{12}^{m}S_{21}^{m}\frac{r_{11}}{1 - {r_{11}S_{11}^{m}}}} - {S_{23}^{m}S_{32}^{m}\frac{r_{33}}{1 - {r_{33}S_{33}^{m}}}}}} & (3) \\{S_{33} = {S_{33}^{m} - {S_{13}^{m}S_{31}^{m}\frac{r_{11}}{1 - {r_{11}S_{11}^{m}}}} - {S_{23}^{m}S_{32}^{m}\frac{r_{22}}{1 - {r_{22}S_{22}^{m}}}}}} & (4) \\{S_{12} = {S_{12}^{m} - {S_{32}^{m}S_{13}^{m}\frac{r_{33}}{1 - {r_{33}S_{33}^{m}}}}}} & (5) \\{S_{13} = {S_{13}^{m} - {S_{12}^{m}S_{23}^{m}\frac{r_{22}}{1 - {r_{22}S_{22}^{m}}}}}} & (6) \\{S_{21} = {S_{21}^{m} - {S_{31}^{m}S_{23}^{m}\frac{r_{33}}{1 - {r_{33}S_{33}^{m}}}}}} & (7) \\{S_{23} = {S_{23}^{m} - {S_{13}^{m}S_{21}^{m}\frac{r_{11}}{1 - {r_{11}S_{11}^{m}}}}}} & (8) \\{S_{31} = {S_{31}^{m} - {S_{32}^{m}S_{21}^{m}\frac{r_{22}}{1 - {r_{22}S_{22}^{m}}}}}} & (9) \\{S_{32} = {S_{32}^{m} - {S_{31}^{m}S_{12}^{m}\frac{r_{11}}{1 - {r_{11}S_{11}^{m}}}}}} & (10)\end{matrix}$

[0099] Likewise, the equations for an n-gate can be determined, wherebythe terms are given higher orders, which contain two and morer_(ii)—Values. These can, however, be disregarded by good approximationapproaches, since the r_(ii)—Values are small, so that each correctioncomputation is given in the form of the solution found under equation(2). For example, for a 4-gate, we have: $\begin{matrix}{S_{11} = {S_{11}^{m} - {S_{13}^{m}S_{31}^{m}\frac{r_{33}}{1 - {r_{33}S_{33}^{m}}}} - {S_{12}^{m}S_{21}^{m}\frac{r_{22}}{1 - {r_{22}S_{22}^{m}}}}}} & (11)\end{matrix}$

[0100] In the following, it shall now be presented, how, with theavailability of the determined dispersion parameter values of a 3-gate,the multimode value of a 2-gate, which encompasses an unsymmetricalentry as well as a two conductor line system, by which a common and adifferential mode occur, can be obtained. The 2-gate, with theunsymmetrical entry can be, for example, a micro strip line and thetwo-line system, for instance can be a two-line system with two parallelmicro strips.

[0101] This procedure is especially of interest where SAW-filter andsymmetrical members are concerned, since here, in contrast to the knownprocedure, the loss mechanisms are separated.

[0102] The unsymmetrical gate for the two-line system comprises thegates 2 and 3 with the wave magnitudes a₂, a₃, b₂, b₃. The de-embeddeddispersion parameters for the three gates are given.

[0103] The unsymmetrical gate is in FIG. 8 the gate 1 with the incomingwave a₁, and the departing wave b₁. The two other gates for the two-linesystem are the gates 2 and 3 with the wave magnitudes a₂, a₃, b₂, b₃.The de-embedded dispersion for the three gates is given.

[0104] On the two-line system, occur a common mode wave and adifferential mode wave, which can be described with the values: a₂ ⁺, a₂⁻, b₂ ⁺, b₂ ⁻. The key for the multimode computation is now, that in alinear system, the mode of the unsymmetrical measurement system allowsitself to be joined with the two-line system, as follows:$\begin{matrix}{a_{2}^{+} = {\frac{1}{\sqrt{2}}\left( {a_{2} + a_{3}} \right)}} & (12) \\{a_{2}^{-} = {\frac{1}{\sqrt{2}}\left( {a_{2} + a_{3}} \right)}} & (13) \\{b_{2}^{+} = {\frac{1}{\sqrt{2}}\left( {b_{2} + b_{3}} \right)}} & (14) \\{b_{2}^{-} = {\frac{1}{\sqrt{2}}\left( {b_{2} + b_{3}} \right)}} & (15)\end{matrix}$

[0105] If one evaluates the equations and defines new dispersionparameters from the usual topography with the wave magnitudes a and b,but with the mode-considerations, whereby an “0” designates theunsymmetrical mode, then there arises the following nine dispersionparameters for the 2-gate with the unsymmetrical entry and thesymmetrical exit.

[0106] The intrinsic parameter for the unsymmetrical mode:

S₁₁=S₁₁  (16)

[0107] The intrinsic parameter for the common mode: $\begin{matrix}{S_{22}^{+} = {\frac{1}{2}\left( {S_{22} + S_{23} + S_{32} + S_{33}} \right)}} & (17)\end{matrix}$

[0108] Intrinsic parameter for the differential mode: $\begin{matrix}{S_{22}^{-} = {\frac{1}{2}\left( {S_{22} - S_{23} - S_{32} - S_{33}} \right)}} & (18)\end{matrix}$

[0109] Conversion parameter for the common mode in the unsymmetricalmode: $\begin{matrix}{S_{12}^{+ 0} = {\frac{1}{\sqrt{2}}\left( {S_{12} + S_{13}} \right)}} & (19)\end{matrix}$

[0110] Conversion parameter for the differential mode in the symmetricalmode: $\begin{matrix}{S_{12}^{- 0} = {\frac{1}{\sqrt{2}}\left( {S_{12} - S_{13}} \right)}} & (20)\end{matrix}$

[0111] Conversion parameter for the unsymmetrical mode in the commonmode $\begin{matrix}{S_{21}^{0 +} = {\frac{1}{\sqrt{2}}\left( {S_{21} + S_{31}} \right)}} & (21)\end{matrix}$

[0112] Conversion parameter for the unsymmetrical mode in thedifferential mode: $\begin{matrix}{S_{21}^{0 -} = {\frac{1}{\sqrt{2}}\left( {S_{21} - S_{31}} \right)}} & (22)\end{matrix}$

[0113] Conversion parameter for the common mode in the differentialmode: $\begin{matrix}{S_{22}^{+ -} = {\frac{1}{2}\left( {S_{22} + S_{23} - S_{32} - S_{33}} \right)}} & (23)\end{matrix}$

[0114] Conversion parameter for the differential mode in the commonmode: $\begin{matrix}{S_{22}^{- +} = {\frac{1}{2}\left( {S_{22} - S_{23} + S_{32} - S_{33}} \right)}} & (24)\end{matrix}$

[0115] Even when the somewhat more closely carried out description of ameasured object with unsymmetrical modes by means of separate dispersionparameters for the common and the differential modes, is based here onthe invented corrected dispersion parameters, it is also possible thatan application of this or a corresponding description could be based ondispersion parameters otherwise determined.

Claimed is:
 1. A procedure for correcting errors by the de-embedding ofdispersion parameters measured with an n-gate (11) encompassing,vectorial network analyzer of a measured object connected with saidgates, whereby the procedure exhibits the following steps: the carryingout of up-to-${{up}\text{-}{to}\text{-}k} = {n \cdot \frac{n - 1}{2}}$

2-gate calibrations on different, calibration standards switched ontothe gates (11) in active state in optional succession as a base for afirst error correction of measured dispersion parameters of a measuredobject and the determination of the reflection parameters of at lestsome of the n gates (11) in the inactive state with the availability ofresults from 2-gate measurements on at least one calibration standardwitched onto the gates (11) in an active and/or an inactive state as abase for a second error correction of at least a part of the measureddispersion parameters, which have been corrected with the said firsterror correction of a measured object.
 2. A procedure in accord withclaim 1, therein characterized, in that, the determination of reflectionparameters of at least one part of the n gates (11) in the inactivestate, is carried out with the aid of the up-to-k 2-gate calibrationswhich became available in the measuring steps for the first errorcorrection.
 3. A procedure in accord with claim 1 or 2, thereincharacterized, in that the reflection parameters of all n gates (11) isdetermined in the inactive state.
 4. A procedure in accord with one ofthe claims 1 to 3, therein characterized, in that in a further step, todetermine the dispersion parameters of a measured object, the dispersionparameters obtained from a first error correction were undertaken on thebasis of the up-to-k 2-gate calibrations, and the thus correcteddispersion parameters, at least partially, underwent a second errorcorrection on the basis of the determined reflection parameters of gates(11) in the inactive state.
 5. A procedure in accord with one of theclaims 1 to 4, wherein, the network analyzer for the measurement of thecalibration standard possesses at least three measurement positionsconnected with, or connectable to, the gates and by which networkanalyzer, in combination with available coaxial or planar calibrationstandards for the 2-gate calibrations as a basis for a first errorcorrection, the following steps are realized and carried out: first,up-to-k calibration measurements are taken on respectively one 2-gate,which, by means of the direct connection of two gates, or by means of ashort matching line of known length and of known damping, which saidline is connected between the k possible gate combinations, a furthercalibration measurement is made on an n-1-gate which, is realized bymeans of n known impedances, and a further calibration measurement ismade on an n-1-gate, which, is realized by means of n known shortcircuits, and an additional calibration measurement is made on ann-1-gate which is realized by means of n known dry runs, whereby thevalue of the parameter represents, respectively, the number n of thegates.
 6. A procedure in accord with one of the claims 1 to 4, whereinthe network analyzer for the measurement of the calibration standardspossesses at least four measurement positions connected to, orconnectable to, the gates, and wherein in combination with availablecoaxial or planar calibration standards, as a basis for the first errorcorrection, it is true that: the calibration standards of all known7-term procedures between the gates in all k possible combinations aremeasured in optional succession.
 7. A procedure in accord with one ofthe claims 1 to 4, wherein the network analyzer for the measurement ofthe calibration standards possesses at least four measurement positionsconnectable to, or connected to the gates and wherein in combinationwith available coaxial or planar calibration standards as a basis forthe first error correction, the following steps are realized and carriedout: first, up-to-k calibration measurements were made on respectivelyone 2-gate, by means of the direct connection of the gates, or by meansof a short matching line of known length and known transmissioncharacteristics which said line is connected between the k possible gatecombinations, further, additional calibration measurements were made onrespectively one 2-gate, by means of a short, matching line of unknownlength and with unknown transmission characterizations, wherein the lineis connected between the possible k gate combinations, and a furthercalibration measurement was made on an n-1-gate, which was executed bymeans of n non-ideal short circuits or dry runs whereby the value of theparameters n represent respectively the number n of the gates.
 8. Aprocedure in accord with one of the claims 1 to 4, wherein the networkanalyzer for the measurement of the calibration standards possesses atleast four measuring positions connected to, or connectable to, thegates, and wherein, in combination with available coaxial or planarcalibration standards as a basis for a first error correction, thefollowing steps are realized and carried out: the up-to-k calibrationmeasurements on respectively one 2-gate, is made by means of the directconnection of the gates or by a short matching line of known length andknown transmission characteristics, which said line is connected betweenthe k possible gate combinations, a further calibration measurement ismade on an n-one gate, by means n-known impedances, and an additionalcalibration measurement is made on a n-one gate, by means of n,non-ideal, short circuits or dry runs whereby the value of the parametern respectively represents the number n of the gates.
 9. A procedure inaccord with one of the foregoing claims, with the usage of known coaxialor planar calibration standards, and which procedure further encompassesthe steps: of measuring the dispersion parameters of a measured objectwhich exhibits symmetrical and unsymmetrical modes and which measuredobject is connected with the gates of the network analyzer, ofcorrecting the measured dispersion parameters with a first errorcorrection on the basis of the up-to-k 2-gate calibration and a seconderror correction on the basis of the determined reflection parameters,resulting in two-fold corrected dispersion parameters, namely S_(ij)where i, j=1 to n, whereby the respective second index identifies thegate, through which a respective wave is saved in the measured object,and the respective first index identifies the gate, through which therespective wave departs from the said measured object, and of thedetermination of separate dispersion parameters for the common and thedifferential modes of the measured object from the two-fold correcteddispersion parameters S_(ij), whereby, for a connected, symmetrical exitof the measured object at an optional gate i and j t, the intrinsicparameters for the common mode are determined at$\frac{1}{2}\left( {S_{ii} + S_{ij} + S_{ji} + S_{jj}} \right)$

and the intrinsic parameters for the differential mode are determined at$\frac{1}{2}\left( {S_{ii} - S_{ij} - S_{ji} + S_{jj}} \right)$

the conversion parameters for the common mode in the differential modeat ${\frac{1}{2}\left( {S_{ii} + S_{ij} - S_{ji} - S_{jj}} \right)},$

and the conversion parameters for the differential mode in the commonmode are determined at$\frac{1}{2}{\left( {S_{ii} - S_{ij} + S_{ji} - S_{jj}} \right).}$


10. A vectorial network analyzer for the determination of the dispersionparameters of a measured object, with n gates (11) for the connection ofmeasured objects and calibration standards as well as having at least 3measuring positions (15), whereby each gate (11) is connected with, orconnectable to at least one measuring position (15) for the capture ofwave magnitudes of signals approaching the gate (11) and connected with,or connectable to a measuring position (15) for the capture of wavemagnitudes of signals departing from the gate 11 as well as possessingmeans for the carrying out of a procedure in accord with one of theclaims 1 to
 9. 11. A vectorial network analyzer in accord with claim 10with exactly three measuring positions (15), characterized by two innergates connected through a switch with said three measuring positions(15) and a switch module (20), which has the capability of connectingthe n-measuring positions through the two inner gates (22) with the saidthree measuring positions (15).
 12. A vectorial network analyzer inaccord with claim 10 with exactly four measuring position (15),characterized by an inner gate connected with two of the four measuringpositions (15) and a switch module (20), which has the capability ofconnecting the n gates (11) through the two inner gates with the fourmeasuring positions.
 13. A vectorial network analyzer in accord withclaim 10 with n+1 measuring positions characterized by one switchmodule, by means of which each of the n gates can be, or is,respectively directly connected with one of the n+1 measuring positions.14. A vectorial network analyzer in accord with claim 10, with 2·nmeasuring positions (15) therein characterized in that, each of the ngates (11) is directly connected with respectively two of the 2·nmeasuring positions (15).